1666845287 has 2 divisors, whose sum is σ = 1666845288. Its totient is φ = 1666845286.

The previous prime is 1666845263. The next prime is 1666845307. The reversal of 1666845287 is 7825486661.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1666845287 - 2⁸ = 1666845031 is a prime.

It is a super-2 number, since 2×1666845287² = 5556746421588224738, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1666845217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833422643 + 833422644.

It is an arithmetic number, because the mean of its divisors is an integer number (833422644).

Almost surely, 2^1666845287 is an apocalyptic number.

1666845287 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666845287 is an equidigital number, since it uses as much as digits as its factorization.

1666845287 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3870720, while the sum is 53.

The square root of 1666845287 is about 40827.0166311476. The cubic root of 1666845287 is about 1185.6734555482.

The spelling of 1666845287 in words is "one billion, six hundred sixty-six million, eight hundred forty-five thousand, two hundred eighty-seven".